Blind phase-shift-based DOA estimation

Blind direction-of-arrival (DOA) estimation algorithms based on direction-vector phase shifts in a uniform linear array are investigated in this paper. Instead of using a pilot signal for training, the output of a blind beamformer is used to compute the phase difference relative to that of a second parallel beamformer. This is possible because the two sets of beamformer weights are related to each other in a specific known manner: (i) they are identical for a subarray approach and (ii) conjugated for a reversed beamformer. Using a least-squares model, these techniques are compared with another blind DOA estimator based on the constant modulus array. Computer simulations are provided to evaluate the performance of the approaches for various cochannel interference and noise conditions.